That means, over the next several years, the number of spots boiling on the sun’s surface is expected to increase. It also means a group of skilled forecasters in Boulder can expect to be busy.

Boulder is home to the nation’s Space Weather Prediction Center, the only agency tasked by the government with forecasting how storms on the surface of the sun may affect systems on Earth, including power grids, high-frequency radio communications, satellite operations and GPS.

The Space Weather Prediction Center is housed at the National Oceanic and Atmospheric Administration’s Boulder campus, along with the local branch of its sister agency, the National Weather Service.

The prediction center is staffed 24/7 by forecasters who sit in front of massive banks of computer screens that monitor the sun and its emissions. Each day at 6 a.m., center staffers get to work updating the two forecasts the group produces: a three-day and a seven-day outlook.

“We start by looking at what’s happened since the forecast yesterday,” said forecaster David Marshall. “We look at the sun first – what’s happening with the existing sunspots, what’s rotating on and what’s rotating off. ... Then we look at everything in the 93 million miles between the sun and the Earth.”

The sun rotates once every 27 days, so individual sunspots are visible to forecasters for 13.5 days before they slip to the other side of the sun. The spots are important to forecasters because they mark the most likely locations where a solar flare might erupt. Intense flares – especially those accompanied by “coronal mass ejections,” which hurl plasma and bits of the sun’s magnetic field out of the corona – can impact Earth when the sunspots are pointed toward us.

Flares can cause three kinds of storms on Earth – radio blackouts, geomagnetic storms and radiation storms – and the prediction center has a rating scale for each that ranges from 1 to 5. Like the hurricane rating system, 1 is the mellowest, and 5 is the most intense.

Understanding the expected magnitude of coming storms before flares hit Earth allows the prediction center’s customers to prepare. For example, airlines that like to fly routes over the poles – which can be quicker and more fuel-efficient than flying across lower latitudes – may choose to rearrange their flight plans during solar storms. That’s because the poles, where the Earth’s own magnetic field gathers and funnels closer to the Earth, are more susceptible to some of the sun’s impacts and therefore can make it more difficult for planes flying in the area to communicate with other planes or back to a base on the ground.

Operations that rely on GPS – which these days is used in more applications from agriculture to smartphone apps – also can be impacted by solar storms, which can throw off GPS measurements as much as a football field in length. This could impact oil companies, for example, that rely on GPS to pinpoint where to drill.

“GPS is really an incredible technology,” said Joe Kunches, a NOAA space scientist who works with the prediction center. “It really grew up in the ’80s and ’90s, and over the next 10 years, these kinds of applications are probably going to push forward as fast as they can. The downside is space weather – is Mother Nature beating on you.”

The sun’s storm activity ebbs and flows in an 11-year cycle. And over the last 11 years, when many GPS applications were being developed, the sun has been relatively tame. But in the next several years, GPS operators may better understand the possible impacts of solar storms.

The recent increase in solar activity is cause for excitement among solar forecasters, who are often kept busy after large solar eruptions by phone calls from customers and the media. But even during the sun’s sleepier years, forecasters are still critical. In part, that’s because large flares can still erupt from the sun at any time, even during a solar minimum, though it’s less common.

But the sun still affects the Earth even without flares with its solar winds. And “coronal holes,” which can impact the solar wind, still form during solar minimums.

And those winds, which buffet the Earth, can cause impacts on our planet, just as shifting wind speeds in the atmosphere can affect airplanes.

In all, there are about a dozen space weather forecasters at the prediction center in Boulder and another two dozen space weather researchers affiliated with NOAA who are working on some of the larger scientific mysteries of solar storms, which may help improve predictions in the future.

“One of the great advantages is we have the researchers and the operations in the same building,” Marshall said.